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This Article Full Text Full Text (PDF) All Versions of this Article: 69/5/1608    most recent biolreprod.102.012534v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Breeveld-Dwarkasing, V.N.A. Articles by van Dissel-Emiliani, F.M.F. Search for Related Content PubMed PubMed Citation Articles by Breeveld-Dwarkasing, V.N.A. Articles by van Dissel-Emiliani, F.M.F. Agricola Articles by Breeveld-Dwarkasing, V.N.A. Articles by van Dissel-Emiliani, F.M.F.

Changes in Water Content, Collagen Degradation, Collagen Content, and Concentration in Repeated Biopsies of the Cervix of Pregnant Cows

Department of Farm Animal Health,² Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands Department of Biochemistry,³ Cell-Biology and Histology, Faculty of Veterinary Medicine, Utrecht University, 3508 TD Utrecht, The Netherlands Gaubius Laboratory,⁴ TNO Prevention and Health, Department of Vascular and Connective Tissue Research, 2301 CE Leiden, The Netherlands

The objective of the present study was to assess if cervical ripeness could be quantified by measuring the percentage of denaturation of the collagen network of the stromal layer. Biopsy specimens from the caudal part of the cervix were obtained from nine pluriparous cows between Days 149 and 157 of gestation (second-trimester biopsy), at exactly Day 275 of gestation (term biopsy), and shortly after calving (calving biopsy). The samples were divided into a superficial stromal part and a deep stromal part. The water content was derived from the weight of the samples before and after lyophilization. A colorimetric assay was used to assess the percentage of collagen denaturation by determining the extinction at 570 nm of hydroxyproline released from -chymotrypsine-treated samples. By incorporating a hydroxyproline standard series in the measurements, the insoluble collagen content (µg/mg dry wt) as well as the insoluble collagen concentration (µg/mg wet wt) could be derived. The water content of both layers of the cervix significantly increased between midpregnancy and parturition (P < 0.01). The insoluble collagen content and the insoluble collagen concentration were significantly increased at term (P < 0.01 and P < 0.05, respectively) but were significantly decreased at calving (P < 0.05 and P < 0.01, respectively). Both parameters showed no significant differences between the superficial and deep stromal layer, and they were significantly correlated with each other. A significant increase in the percentage denaturation of the deep stromal layer occurred between the second trimester and term pregnancy (P < 0.01), whereas at calving, the percentage denaturation had not significantly increased compared to term. The percentage of collagen denaturation of the superficial stromal layer did not significantly change with stage of gestation or at parturition. Our findings indicate that cervical ripening is a combination of increased collagen synthesis and increased percentage of collagen denaturation, whereas at calving, an increased digestion of the denatured collagen leads to increased collagen loss from the cervical connective tissue. The finding that cervical ripening mainly takes place in the deep stromal layer of the cervix emphasizes the importance of a detailed description of the tissue sampling sites for a proper interpretation of the results obtained from biochemical studies of the cervix.

¹ Correspondence: V.N.A. Breeveld-Dwarkasing, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands. FAX: 31 0 30 2521887; v.n.a.dwarkasing{at}vet.uu.nl

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